Uses of immunologically modified scaffold for tissue prevascularization cell transplantation

Abstract

This invention provides method of making and using of a porous 3 dimensional cyclic RGD peptide-modified alginate scaffold that can be loaded with different cell types and/or growth factors for implantation at sites of tissue damage to promote tissue regeneration. The cyclic RGD peptide promotes vascular formation of the host tissue, cell binding and survival of seeded cells. Scaffolds with growth factors but without cells can also be implanted to create a vascular bed in which cells are transplanted at a later time point.

1 . A porous three dimensional scaffold comprising purified alginate molecules that are conjugated to cyclic RGD peptides. 
   
   
       2 . The porous three dimensional scaffold of  claim 1 , wherein the alginate molecules are poly-mannuronic or poly-guluronic acid molecules. 
   
   
       3 . The porous three dimensional scaffold of  claim 1 , wherein the cyclic RGD peptides comprise a sequence RGDxy, wherein “x” is phenylalanine or tyrosine, and “y” is cysteine, glutamic acid, lysine or valine. 
   
   
       4 . The porous three dimensional scaffold of  claim 1 , wherein the alginate molecules are purified to contain less than 0.305% protein. 
   
   
       5 . The porous three dimensional scaffold of  claim 1 , wherein the alginate molecules are purified to contain less than 12.5 EU endotoxin per gram dry alginate. 
   
   
       6 . The porous three dimensional scaffold of  claim 1 , further comprising one or more components selected from the group consisting of cells, immunomodulatory factors, and growth factors. 
   
   
       7 . The porous three dimensional scaffold of  claim 6 , wherein the cells are stem cells, myocytes, human bone marrow derived mesenchymal precursor cells, or islet cells. 
   
   
       8 . The porous three dimensional scaffold of  claim 6 , wherein the growth factors are PDGF, VEGF, or thymosin beta 4. 
   
   
       9 . The porous three dimensional scaffold of  claim 6 , wherein the immunomodulatory factors are antibodies, synthetic drug or peptide. 
   
   
       10 . The porous three dimensional scaffold of  claim 1 , wherein the alginate molecules are purified by a method comprising the steps of dissolving the alginate molecules in an acidic buffer; removing protein, DNA, RNA and endotoxin by neutral and active charcoal treatment, and purifying by filtration through bioactive filter membranes and precipitation with ethanol. 
   
   
       11 . A composition comprising the porous three dimensional scaffold of  claim 1 . 
   
   
       12 . A method of promoting tissue or cell transplantation, comprising the steps of:
 i. preparing a porous three dimensional scaffold of  claim 1 ;   ii. loading the porous three dimensional scaffold with cells or tissue; and   iii. transplanting the loaded porous three dimensional scaffold into a human or animal, thereby obtaining better transplantation results as compared to transplantation without the porous three dimensional scaffold.   
   
   
       13 . The method of  claim 12 , wherein the cells are stem cells, myocytes, human bone marrow derived mesenchymal precursor cells, or islet cells. 
   
   
       14 . The method of  claim 12 , wherein the porous three dimensional scaffold further comprises one or more immunomodulatory factors or growth factors. 
   
   
       15 . A method of promoting tissue or cell transplantation, comprising the steps of:
 i. creating a vascular bed by transplanting a porous three dimensional scaffold of  claim 1  into a human or animal; and   ii. transplanting cells or tissues into the vascular bed, thereby obtaining better transplantation results as compared to transplantation without using the porous three dimensional scaffold.   
   
   
       16 . The method of  claim 15 , wherein the cells are stem cells, myocytes, human bone marrow derived mesenchymal precursor cells, or islet cells. 
   
   
       17 . The method of  claim 15 , wherein the porous three dimensional scaffold further comprises one or more immunomodulatory factors or growth factors. 
   
   
       18 . A method of promoting cell transplantation to heart, comprising the steps of:
 i. preparing a porous three dimensional scaffold of  claim 1 ;   ii. loading the porous three dimensional scaffold with stem cells or myocytes; and   iii. transplanting the loaded porous three dimensional scaffold into a heart, thereby obtaining better transplantation results as compared to transplantation without the porous three dimensional scaffold.   
   
   
       19 . The method of  claim 18 , wherein the porous three dimensional scaffold further comprises one or more immunomodulatory factors or growth factors. 
   
   
       20 . The method of  claim 19 , wherein the immunomodulatory factor or growth factor is PDGF, VEGF, or thymosin beta 4.